- ItemElucidating the life history and ecological aspects of Allodero hylae (Annelida: Clitellata: Naididae), a parasitic oligochaete of invasive Cuban tree frogs in Florida(Allen Press, 2015)Given their ubiquitous nature, it is surprising that more oligochaete annelid worms (Annelida: Clitellata) have not adopted an endoparasitic lifestyle. Exceptions, however, are the understudied members of the genus Dero (Allodero) that parasitize the ureters of tree frogs and toads. This study experimentally explores the life cycle and host specificity of Allodero hylae, the worm's use of chemical cues in host searching, and its seasonal prevalence and abundance over a year-long collection period on the Florida Southern College campus. A total of 2,005 A. hylae was collected from the ureter, urinary bladder, or expressed urine of wild Osteopilus septentrionalis; a significant positive correlation was found between host snout–vent length and parasite intensity for female but not male hosts. Monthly prevalence of A. hylae reached a peak of 58% in April, but never dropped below 20% in any month; mean abundance peaked March–May, whereas few worms were recovered in December and January. Confirming a parasitic lifestyle, wild-collected hosts with intense infections, typically >40 worms, showed obvious dilatation of the ureter wall, and some young-of-the-year O. septentrionalis exposed to A. hylae in the laboratory were killed by the apparent rupture of the host's ureter. The worm has a direct life cycle: worms expelled in the host's urine are capable of locating and re-infecting other hosts within aquatic microhabitats such as bromeliad tanks, and worms can survive for weeks in a free-living environment, even undergoing a morphological change. Further, chemotaxis assays found a positive response to a tree frog attractant for worms recently removed from hosts. Overall, this study provides the first multifaceted investigation on the life history and ecology of any Allodero spp., which offers new insights into an understudied endoparasitic oligochaete.
- ItemPeptide examination and study tool: An online learning interface for amino acids and peptides in the introductory biochemistry classroom(John Wiley & Sons, 2020-11)As proteins are essential to biological processes, knowledge about amino acids, and the peptide structures they form is fundamental to understanding biochemistry. In the introductory biochemistry course, mastering this concept is often a major cognitive hurdle for students.1 This task can be especially difficult within a distance learning environment as students may experience difficulties staying engaged during lengthy remote lectures.2 To supplement remote instruction of these basic principles, we have designed a program that helps students memorize the properties of amino acids and practice determining the isoelectric point (pI) of a peptide sequence. This program consists of five components and is available on the web at http://pest.epizy.com/.
- ItemRapid Pivot of CURE Wet Lab to Online with the Help of Instructor Communities(American Society for Microbiology, 2022)The pivot to remote and hybrid learning during the Covid-19 pandemic presented a challenge for many in academia. Most institutions were not prepared to support this rapid change, and instructors were left with the burden of converting a traditional face-to-face course into multiple modalities with very limited preparation time. When institutional support is lacking, we posit that instructor communities of practice can help provide the resources needed to meet the instructional demands. Tiny Earth, a course-based-undergraduate research experience (CURE) and international network of instructors and students, responded to the instructional challenges of the pandemic by leveraging its large community of instructors to create several smaller working groups to form focused communities of practice. Using the pedagogical principles of backward design and scientific teaching, one working group, the Tiny Earth Pivot Group (Pivot Group) generated a course map of remote learning activities and simulated learning resources to fulfill the Tiny Earth learning objectives and maintain the essential tenets of a CURE. Additional working groups were created to disseminate the resources collated and created by the Pivot Group to the greater community. In terms of Tiny Earth, the community structure provided the means for instructors to rapidly pivot their course materials to multiple modalities while upholding the student CURE experience. Harnessing the hallmarks of communities of practice—collective workpower toward common purpose, diversity of perspectives, and ongoing evolution—coupled with high-structured course design allows instructors flexibility and adaptability in meeting the changing modalities of higher education.
- ItemA cnidarian phylogenomic tree fitted with hundreds of 18S leaves(bioRxiv, 2022-10-05)Cnidarians are critical members of aquatic communities and have been an experimental system for a diversity of research areas ranging from development to biomechanics to global change biology. Yet we still lack a well-resolved, taxonomically balanced, cnidarian tree of life to place this research in appropriate phylogenetic context. To move towards this goal, we combined data from 26 new anthozoan transcriptomes with 86 previously published cnidarian and outgroup datasets to generate two 748-locus alignments containing 123,051 (trimmed) and 449,935 (untrimmed) amino acids. We estimated maximum likelihood phylogenies for both matrices under partitioned and unpartitioned site-homogeneous and site-heterogenous models of substitution. We used the resulting topology to constrain a phylogenetic analysis of 1,814 small subunit ribosomal (18S) gene sequences from GenBank. Our results confirm the position of Ceriantharia (tube-dwelling anemones), a historically recalcitrant group, as sister to the rest of Hexacorallia across all phylogenies regardless of data matrix or model choice. We also find unanimous support for the sister relationship of Endocnidozoa and Medusozoa and propose the name Operculozoa for the clade uniting these taxa. Our 18S hybrid phylogeny provides insight into relationships of 15% of extant taxa. Together these data are an invaluable resource for comparative cnidarian research and provide perspective to guide future refinement of cnidarian systematics.
- ItemExploring Differential Gene Expression Profiles Of Dero (Allodero) Hylae In Their Parasitic And Free-Living Forms(bioRxiv, 2022-06-18)Parasitism is ubiquitous in nature, yet little is known about the evolutionary mechanisms that lead to a parasitic lifestyle. Facultative parasites can switch between free-living and parasitic lifestyles, which may provide an opportunity to study the genetic mechanisms underlying a transition to parasitism. The oligochaete Dero (Allodero) hylae is a facultative parasite commonly found within the ureter of various anuran species, such as the Cuban Tree Frog (Osteopilus septentrionalis). Dero hylae makes passage through the frog’s cloaca, where it then infects the ureter. In the ureter, the worm loses free-living characteristics such as hair setae, dorsal setae, a digestive tract, and fossa with gills as it transitions to a parasitic lifestyle. Dero hylae may be expelled from its host during urination, when this occurs the worm will reacquire free-living characteristics. The focus of this study is to compare the differential gene expression profiles observed when this rapid morphological change takes place. Specimens of D. hylae were collected from wild Cuban Tree Frogs and either flash-frozen for their parasitic stage RNA profile or cultured for two weeks to produce their free-living stage and then flash-frozen. Using the sequenced RNA, a de novo transcriptome was assembled and differential gene expression RNA Tag-Seq analysis between the free-living and parasitic life forms was analyzed. Based on these results, we have identified 213 genes differentially expressed transcripts between the two life forms, 190 of these being up-regulated in the free-living life form. While over half of the differential genes recovered did not recover any significant BLAST hits, many of these genes did provide insight into which molecular signals are potentially used by D. hylae to lose and subsequently regrow their setae, digestive tract, and gills. This analysis provides significant insight into which differentially expressed genes are linked to drastic morphological changes observed in this rare oligochaete parasitism across the free-living and parasitic forms of D. hylae.